The present work investigates the exciton-LO phonon interaction in a semiconductor spherical quantum dot. Through a variation method, a fully detailed analysis of contributions is given. The exciton-LO phonon interaction is studied in two different cases: (i) with a finite confining potential surrounding the quantum dot and (ii) with a infinite confining potential. The calculation for different material such as CdSe/ZnSe and GaAs/Al xGa1-x As, shows that the interaction energy is increasing with increasing the quantum dot radius. Also it has been observed that the interaction energy for QDs with finite confining potential is higher than these with infinite confining potential, furthermore because of confinement potential variation with Al molar fraction in GaAs/AlxGa1-x As QDs a different behavior for interaction energy has been achieved at different Al molar fraction. © 2012 Elsevier GmbH.